The biggest risk factors include family history and pregnancy. Genetics is a primary cause, and it has been suggested that if both parents have CVI, their children have a 90% chance of having CVI at some point. If one parent has CVI, then women have ~60% chance and men a 25% chance of having it. If neither parent has it, then both men and women have a 20% chance.
Pregnancy is a key factor contributing to the formation of varicose and spider veins. The most important factor is circulating hormones that weaken vein walls.
There is also a significant increase in the blood volume during pregnancy, which tends to distend veins. This causes valve dysfunction which leads to blood pooling in the veins. Varicose veins that form during pregnancy may spontaneously improve or even disappear a few months after delivery.
Other risk factors include standing or sitting for long periods of time during the day (especially fields such as nursing, teaching, hairdressing, or factory jobs), advancing age, prior injury or surgery in the legs, and obesity.
Risk Factors for Varicose Veins
- Family history/genetics
- Pregnancy, especially multiple pregnancies
- Older age
- Female gender
- Prior surgery or trauma